This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Sweden Patent Application No. 0101315-0 filed on Apr. 12, 2001, the entire content of which is incorporated herein by reference.
In many different applications of bearings supporting rotary loads, it is of great interest to know not only the rotational speed of the rotating shaft supported in a bearing disposed in a bearing housing, but also other parameters influencing the function of the bearing and/or indicating the condition of the bearing. Such other parameters are temperature and vibration. It is necessary to position a temperature sensing device inside the bearing housing as it is the actual internal temperature, which is of importance. It is also convenient to position an appropriate measuring device for recording the rotational speed inside the bearing housing as the rotating bearing race ring and the shaft are available therein and the sensor and the measuring device will have a comparatively protected position therein. Probably mostly for space reasons, vibration sensors have not been located inside the bearing housing, but have instead been positioned externally on the outside of the bearing housing, either on top of the bearing housing or on the upper side of the bearing housing base, where they can be fitted at especially prepared surfaces permitting correct positioning of the sensors in relation to the shaft. However, this earlier used positioning of the vibration sensors has some drawbacks, mainly due the fact that the sensors are positioned so that they project somewhat outside the rigid bearing housing wall and therefore might be subjected to influence from the surroundings, such as impacts, humidity and dirt.
The bearing housings in question can be of the type having lower and upper parts. The lower part includes a base portion on which is arranged a lower half of a bearing housing with an internal bearing, a seat, and having end openings for a shaft. The upper part of the bearing housing is connectable to the lower part by bolts. The base portion of the lower part is equipped with bolt holes for fitting the bearing housing to a frame. The lower side of the base portion in recent years has been provided with cavities opening towards the bottom of the base portion. The purpose of such cavities is primarily to reduce weight. Moreover, due to the fact that the provision of the cavities serves to reduce the area of the lower side of the base which rests upon the bedding or frame to which the bearing shall be attached, the difficulties involved in leveling the bearing housing base are reduced.
An object of the present invention is to provide a bearing housing with a measurement device for sensing vibration, which eliminates the above drawbacks.
The present invention relates to a bearing housing which includes a base portion that has a bottom exterior surface in which a cavity arrangement is formed. At least two vibration-detecting sensors are disposed within the cavity arrangement and are situated therein completely interiorly with respect to a plane defined by the bottom exterior surface. The sensors are arranged to detect vibrations in two perpendicularly opposed directions.